Telephone instrument



June 17, 1941.

R. F. STEHLIK TELEPHONE INSTRUMENT Filed May 11, 1939 INVENTOR. RUDOLPHFRANK STEHL/K Patented June 17, 1941 r Tau-reg ons ms'raurmn'r .BudolphFrank Stehllk, Antwerp, Belgium, as

signer to Associated Telephone & Telegraph. Company, Chicago, 111., acorporation oi Delaj ware Application May 11, 1939, Serial No. 272,951In Great Britain May 18, 1938 2 Claims- (Cl. 179-403) I phonetransmitter to'the mouth, for instance when wearing a gas mask.

In such circumstances it is known to provide a throat transmitter orso-called laryngaphone in addition to the normal telephone instrument.This has usually been provided as a separate unit which can be strappedaround the neck and connected by a cord to the terminals of theinstrument which incorporates a switching device permitting the cuttingout of the handset transmitter and the switching-in of the laryngaphone.This arrangement has certain disadvantages as if it is necessary tolisten as well as to speak, the receiver of the handset must still beheld to the ear. Moreover the separate unit with straps and cord isawkward to handle and store and under certain conditions the cord andstrap are liable to become tangled and .furthermore a switch has to beprovided on the instrument and an extra operation is necessary to renderthe laryngaphone effective. The chief object of the present invention isto provide a neat and compact combined telephone and laryngaphone unitwhereby the above difiiculties are avoided.

According to one feature of the invention in a telephone handset a unitincluding a receiver and microphone of ordinary type is provided with asocket for the plugging in of a throatoperated microphone.

According to another feature of the invention in a telephone handset aunit including a receiver and microphone of ordinary type is providedwith facilities for plugging in a throat-operated microphone insubstitution for the ordinary microphone.

The invention will be better understood from the following descriptionof one method of carrying it into efiect which should be taken inconjunction with the accompanying drawing comprising Figs. 1-4. Ofthese,

Fig. 1 shows the normal handset,

Fig. 2 shows the plug-in portion comprising the laryngaphone,

Fig. 3 is a fragmentary view showing the laryngaphoue in plugged-inposition and indicating the contact operation produced thereby, whileFig. 4 represents a suitable circuit diagram. It will be seen that thehandset comprises the usual receiver I and microphone transmitter 2Joined by the handle 3 which is split longitudinally and provided withthe switching key 4 for connecting up the talking battery. The handlealso includes the socket 5 adapted to receive the laryngaphone of Fig.2. This comprises essentially the member 0 which is pressed against thethroat to receive the speech vibrations and the plug portion I whichfits into the socket 5 and makes the necessary electrical connections.As will be seen from Fig. 3 the plug spring I engages the spring 8 andmoves it out of contact with the spring 8 thereby breaking theconnection to the ordinary microphone and connecting up the laryngaphonein its place. It will be seen from the circuit diagram of Fig. 4 thatthe complete instrument includes a magneto It with the usual switchingsprings II and control contacts II, a bell I3, induction coil I4, buzzerl5, signalling key l1, and battery It.

These are connected in a more or less conventionalmanner to theterminals l9 and 20 extending to the line.

The laryngaphone element is conveniently housed in a casing of mouldedmaterial but metal or rubber may also be used if found more convenient.Moreover though in the system shown the plugging-in of the unitdisconnects the ordinary microphone this is not essential and it mightbe thought desirable in some cases for both to remain connected up. Itwill be seen that the pin connections are sufiiciently long and robustfor the laryngaphone to be held firmly in position after it has beenplugged in. Its rigidity is increased by the fact that it secures abearing against the projection 2| on the mouthpiece 2. It will be seenalso that the shape and location of the unit are such that when it isplugged in the handset can be used with comparatively little change inposition.

According to the invention therefore a very simple construction has beendevised whereby a normal handset can be readily adapted to operationwith a throat microphone with the minimum of additional equipment andthe utmost convenience.

Iclaim:

1. A telephone handset unit having a handle carrying the usualtransmitter and receiver thereon, a throat operated microphone having atransmitter on one end and a receiver on the 10 other end, alaryngaphone having a plug extension rigid therewith, a socket in thehandle between the transmitter and receiver and adjacent thetransmitter, a built out projection on the transmitter adjacent thesocket, said projection and said socket cooperating to hold thelarynga'phone rigidly supported on the handle above the transmitter whenthe plug is inserted in the socket.

RUDOLPH FRANK S'I'EHLIK.

